Potential Blown Engine-2003 XR-6?

[Lovgren69]

Looking for advice from people out there who might have experienced a similar failure!!!

Engine: 2003 Mercury XR-6

Condition: Maintained yearly, run Merc. Premium Plus Oil

Problem: Warmed my engine up the other day for a minute or so and took off down the river. Engine was beeping to indicate low oil, but it does this anytime the engine reserve is lower than 3/4 full, so I didn't think anything of it. Remote Oil resevoir had 2+ gallons.

Ran engine up to 5500 rpm @ top speed, had it trimmed up as high as it goes without blowing out, and appeared to be running fine. Ran the engine for about 1/2 mile or so and then all of a sudden the engine bogged down and preceeded to make a terrible sounding grinding/clanking noise. I powered the engine down and shut it off to inspect. I did hear a wierd humming noise before all this happened, but of course I didn't realize what was happening!!

Checked the engine oil resevoir and it was low, but not out of oil. Started the engine back up and let it idle, again the engine was making a grinding/clanking noise. Shut it down and ran the kicker to get back to the dock.

Before I take the motor to get checked, I just wanted to see if anyone out there might have an idea of what happened, and what the severity of the repairs I am possibly looking at?

I don't see anything good with the above scenario, and I'm worried that I will need to have the powerhead replaced along with any other damage the engine might have experienced...

It will be a tough decision since that particular motor in good working condition is probably only worth 4500-5000 dollars, so I'm keeping my fingers crossed that the repairs don't come close to that number.

[ejj]

Are you sure the alarm was for the oil? My temperature alarm sounds the same/similar as the oil alarm. If your impeller/water pump is shot you probably lost the top cylinder, perhaps more. Doesn't sound cheap.

[perchjerker]

if you had 2+ gallons of oil and then after this happened you had low oil, sounds like you have an oil leak, maybe it starved the engine for oil? Where did the 2 gals of oil go in that short a period of time? Did you look in the bildge?

sorry to hear about this!!!

[MarkG]

One thing you can easily check is to see if you blew a piston. Borrow a compression tester from a gearhead friend. Compression is easy to check. Pull the spark plugs,screw the tester in place of the spark plug. Pull the lanyard safety cutoff switch ,so the spark will be disabled and the motor won't start.

Then spin the motor for about 1 second or what ever it takes to get about 4 compression strokes,with the electric start. Tester Will measure psi. On carbed models supposed to do this with the throttle wide open. (Not sure about EFI.) Do this on every cylinder.

If good compression should show "about" 100PSI and all cylinders should be within about 10% of each other. If you blew a piston or rings or scored the walls in any cylinder this will tell you,PSI will be noticably lower to near non existent. If good compression in all,may have broken something else like a rod or damaged any number of bearings, etc. Although any failure of the nature mentioned will likely require a new power head. I don't believe that in outboards they replace individual pistons,like they can in snowmobile and other types of motors.

Here is what a compression tester looks like:
http://www.amazon.com/gp/product/B000RFQNWM

If you end up replacing a powerhead,then they also have to diag WHY it blew. They generally just don't do it on their own.
Could be an oiling problem,cooling,carburation (too lean) an intake problem causing it to be sucking air (again too lean) etc. Just replacing the powerhead without figuring out why may doom it to repeat.

[eye4aneye]

Overheat issue is a possiblity. Even a lower unit failure.

In my experience, you can usually tell how bad things are on the motor by looking thru the spark plug holes. If one of the cylinders looks like you threw a handful of aluminum in there . . .

Good news is you can find some bargains on used outboards if you shop around and that motor is pretty common.

[Lovgren69]

For those of you who posted, thanks for steering me in the right direction.
I went to check the compression today, and didn't even get that far!

After removing all 6 plugs, I found that one of the pistons appeared to be blown. The mating spark plug electrode was covered with a silvery metalic residue, which appeared as a hard mass. I'm presuming that part of the piston or cylinder head melted causing this deposit.

The other 5 plugs appeared normal and showed a light tan appearance. None of the other plugs appeared to be fouled due to excessive carbon/oil build-up.

Best case scenario, assuming everything else is in working condition--does anyone have any estimates as to what the repair(s) are going to involve--parts wise and price wise??

Obviously if I elect to get the motor repaired, I will need to isolate what caused the failure in order to prevent this type of failure from happening in the future....

Thanks to all for the helpful information.

[T Mac]

As for advice...
Personally, I get nervous when an alarm is going off.

[darin]

I can't tell you how many times I read about people rebuilding engines, only to have them fail a few hours afterward. I don't know what your cash situation is like, but I'm inclined to feel that the money spent rebuilding is perhaps wiser spent on a new(er) engine. Sometimes you can find pretty good deals on engines that still have some warranty, too. Sorry to hear about your misfortune... good luck.